feat(openapi): allow external $refs

[acsauk]

Hey @outofcoffee - thanks for the config pointers, that fixed the issue I was seeing. However, I ran into another problem as some of our mocks rely on external references for component schemas, which, after some digging, I could see wasn't supported.

I've made as minimal a change as possible, not being too familiar with this codebase, so let me know of any changes you want. I also wasn't too sure at what level to test this at, the parser level seemed appropriate but again happy to make changes if you want this further up the stack.

[outofcoffee]

Thank you very much for this @acsauk. You've also prompted us to update the config schemas to bring them into alignment with the current data model.

This change looks good - how would you feel about us moving the new property under the plugin-specific config key, e.g.

plugin: openapi
specFile: users-external-ref.yaml

config:
  externalBaseURL: http://example.com

resources:
  - path: /users
    method: GET
    response:
      statusCode: 200

We're considering this as the place for plugin-specific configuration, so, eventually, things like specFile would move there too, albeit with backwards compatibility for existing files.

[acsauk]

Hi @outofcoffee apols for the delay, I'm just back from annual leave.

The config key is a good call - I'll push an update to the PR later today 👍

[acsauk]

Hi @outofcoffee is there anything else you need changing for this?

[outofcoffee]

Thanks very much for this feature. Docs will be updated shortly after this is merged.